Qeustion about linked list

[Jakiro]

I have some question about linked list.
how to complete the delete and search function??

#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
 
 
struct ProductNode{
    char code[5];
    char description[30];
    double price;
    ProductNode *Next;
};
 
typedef ProductNode *Productptr;
 
void Display(Productptr );
Productptr Search(Productptr, char []);
void Delete(Productptr *, char []);
void Insert(Productptr *, ProductNode);
 
main(){
    Productptr PhoneList,temp;
    ProductNode p;
    int sel;
    char id[5];
 
    PhoneList = NULL;
 
    while (sel != 5){
        system("cls");
 
        cout<<"\t1. Add Item."<<endl;
        cout<<"\t2. Add Delete."<<endl;
        cout<<"\t3. Display Item."<<endl;
        cout<<"\t4. Search."<<endl;
        cout<<"\t5. Exit"<<endl;
        cout<<"\t? : ";
        cin>>sel;
 
        system("cls");
 
        switch (sel){
            case 1: cout<<"Item Code :";
                    cin>>p.code ;
                    cout<<"Description : ";
                    cin>>p.description;
                    cout<<"Price : RM ";
                    cin>>p.price;
                    Insert(&PhoneList, p);
                    break;
 
            case 2: cout<<"Item Code :";
                    cin>>id ;
                    Delete(&PhoneList, id);
                    break;
 
            case 3: Display(PhoneList);
                    break;
 
            //case 4: cout<<"Enter item's Code : ";
            //        cin>>id;
 
            //        temp =  Search(PhoneList, id);
            //        if (temp == NULL)
            //            cout<<"Error : Item not Found."<<endl;
            //        else{
            //               cout<<"Code\tDescription\tPrice\n";
            //            cout<<"====\t===========\t=====\n";
            //            cout<<temp->code<<"\t"
            //                <<temp->description<<"\t\t"
            //                <<temp->price<<endl;
            //            }
                    system("pause");
        }    
    }
    return 0;
}

[Meetee]

I have some question about linked list.
how to complete the delete and search function??

}

That will be equal to giving you a source code. Better you refer the following link for explanation of Linked list. Google for further information.

Linked List Tutorial

Regards

[Jakiro]

if i get something like this .
no error but can't delete the item i want .
somone can help me toubleshoot?



void Delete(Productptr *r, char id[5])
{
Productptr *temp;
Productptr *temp2;
bool found;
if(r==NULL)
cout<<"Cannot delete from and empty list."<<endl;
else
{
temp=r;
found= false;

while(temp!=NULL && !found)
if (strcmp((*temp)->code,id)<=0)
found=true;
else
{
temp2=temp;
(*temp)=(*temp)->Next;
}
if(temp==NULL)
cout<<"Item to be deleted is not in the list."<<endl;
else
if(strcmp((*temp)->code,id)==0)
{
if(r==temp)
{
(*r)=(*r)->Next;
delete temp;
}
else
{
(*temp2)->Next=(*temp)->Next;
delete temp;
}
}
else
cout<<"Item to be deleted not in list."<<endl;
}

}

[sksriharsha]

Hi,

1. It will be better if you posted code within the CODE Tags.

void Delete(Productptr *r, char id[5])
{
Productptr *temp;
Productptr *temp2;
bool found;
if(r==NULL)
  cout<<"Cannot delete from and empty list."<<endl;
else
{
  temp=r;
  found= false;
 
  while(temp!=NULL && !found)
  if (strcmp((*temp)->code,id)<=0)
    found=true;
  else
  {
    temp2=temp;
    (*temp)=(*temp)->Next;
  }
  if(temp==NULL)
  cout<<"Item to be deleted is not in the list."<<endl;
  else
  if(strcmp((*temp)->code,id)==0)
   {
     if(r==temp)
     {
       (*r)=(*r)->Next;
       delete temp;
     }
     else
     {
        (*temp2)->Next=(*temp)->Next;
        delete temp;
     }
   }
   else
   cout<<"Item to be deleted not in list."<<endl;
 }
 
}

2. Is this exactly the code you have tried?? Because, the while loop does not have a begin brace...

3. What does

if (strcmp((*temp)->code,id)<=0)

mean in this context?? Shouldn't it be just

if (strcmp((*temp)->code,id)==0)

4. Shouldn't the control return to main() once r==NULL?